


Koro-sensei has some fun

by orphan_account



Category: Assassination Classroom
Genre: Early Christmas Gift, Group Sex, M/M, Multi, Rape/Non-con Elements, Students, Teacher-Student Relationship, Tentacle Monsters, Tentacle Rape
Language: English
Status: Completed
Published: 2018-12-09
Updated: 2018-12-09
Packaged: 2019-09-13 19:06:55
Rating: Explicit
Warnings: Rape/Non-Con, Underage
Chapters: 1
Words: 1,938
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16898250
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: Nagisa and Karma devise a plan to assassinate Koro-sensei and things go horribly wrong.





	Koro-sensei has some fun

Karma and Nagisa had been planning their assassination attempt for a while now, and today was the day that they were finally putting their plan into action. Karma had expected Nagisa to back out of the plan by now since Nagisa played a central role (his job was to distract Koro-sensei), but Nagisa hadn't to his surprise.  
After two months of preparing and practicing, they were both ready. They waited until Koro-sensei was alone after school and the plan went into motion.  
If only they knew what they were really getting into.

 

Koro-sensei sat at his desk simultaneously reading a porn mag while he graded the students homework. He heard the door open and turned to see Nagisa enter the room dressed in the same outfit he had worn on the island back when the class had gone to Okinawa in order to sneak into a club unnoticed with his female classmates. 

Koro-sensei raised an eyebrow. What as Nagisa doing here in that outfit? "Do you need something, Nagisa-kun?" He asked, quickly hiding his porn mag before the boy could notice it. "Tutoring, perhaps?" He figured that Nagisa was here to make an assassination attempt and chuckled quietly. 

"Something like that," Nagisa strutted across the room and leaned seductively against Koro-sensei's desk. "Although, I need another sort of tutoring right now."

"Oh?" Koro-sensei recognized immediately what Nagisa was doing. Irina had tried this on him multiple times already, he must have received some tips from her. Stifling a laugh, Koro-sensei decided to play dumb. "Really? What kind of tutoring?" 

Nagisa bit his lip, hesitating only for a moment. From the vents, Karma watched hoping that Nagisa would be able to continue. Nagisa straightened himself and gripped the hem of his skirt. 

"Sensei, could you tutor me in sex education?" He asked coyly, "I could really use an experience teacher to show me how it works." With that, he lifted his skirt revealing his lower regions. Not wearing any underwear, Nagisa only had a bow, like the kind on a gift box, covering his penis presenting himself as an early Christmas present. 

Koro-sensei stared at Nagisa. This part was unexpected, but he licked his lips anyway trying his best to hide his anticipation. This was going to be fun. 

"Wow, Nagisa-kun. I didn't peg you for this type of person," Koro-sensei grinned, stroking his chin and eyeing Nagisa's lower regions. "What brought this about all of a sudden?" It took all of his willpower not to rip of the bow and begin fucking the boy immediately. He licked his lips again, wondering how far Nagisa will let him go before he attempted to kill him.

Nagisa smiled, still holding up his skirt up. "I have always been attracted to you, Sensei. For months I have been dreaming of you fucking me at mach speed until I passed out," Nagisa shivered. "It's all I ever think about."

Koro-sensei's grin widened. He had already been planning on raping Nagisa for months and now here he was presenting himself on his own.

"Please, Sensei." Nagisa put on his most imploring face. "Won't you indulge me?" 

"Don't mind if I do," Koro-sensei reached out a tentacle and removed the bow on Nagisa's penis leaving his lower regions completely exposed. Nagisa's penis was bigger than he expected, nearly six inches and just thick enough to be perfect. Wrapping a tentacle around Nagisa penis, he began to stroke it while another tentacle removed his skirt and two more slithered up his legs.

Nagisa eyes shifted towards the ceiling. Suddenly, Karma drops from the vents landing on Koro-sensei's back. Quicker than lighting he withdraws his blade and stabs at Koro-sensei's head.

Koro-sensei hadn't been expecting Karma to be hiding in the vents. The two students would have successfully killed him if Nagisa hadn't looked at the ceiling unintentionally warning Koro-sensei with the small gesture. 

Smiling wickedly, Koro-sensei's tentacles ensnared Karma and immediately threw him across the classroom. Karma slammed into the wall and slide to the ground. Before he can get up, Koro-sensei stretched out his other tentacles and wrapped them around his arms and legs keeping him restrained against the wall. 

"You two almost had me!" He giggles. "Now you both get to receive punishment!" 

In an instant Koro-sensei stripped both boys until both were completely naked. He compares the two boys; Nagisa was smaller and more delicate with a frame closer to a girl's than male's. Karma was more muscular and well built, his own penis two inches bigger and much thicker than Nagisa's. 

Karma and Nagisa struggled uselessly.

"Let us go!" Karma shouted. "You can't rape us!"

"Yes I can," Koro-sensei said cheekily. "Nagisa already offered himself up anyway, so technically i'm not raping him. I'm just giving in to his desires~!"

"I-I was only pretending for the sake of the assassination!" Nagisa protested, blushing wildly. "I don't actually want this!" 

"Hmmm~? If you were only pretending then there wasn't any need to go as far as to show me your penis, Nagisa-kun." Koro-sensei smirked. 

"Then let Karma go and just take me instead!" Nagisa pleaded. "He didn't ask for this!" 

"Nagisa!" Karma's eyes widened. "You don't need to sacrifice yourself for me. We'll kill him together." 

"Not today," Koro-sensei giggled again, moving Karma closer to him. "I'm going to have some fun with the two of you first~!" Koro-sensei tightened his grip on the boy's arms and legs. He reaches into the drawer of his desk and pulls out two sets of handcuffs. He handcuffed them then forced them to lean on his desk so they could brace themselves. The two boys are bent over and they gripped the edge of desk with their butts presented to Koro-sensei. Both of them have given up struggling and tremble as the wait for Koro-sensei's punishment. 

Koro-sensei admires their asses; Nagisa' plump heart-shaped butt and Karma's more firm butt. Tickling their assholes with his tentacles he wondered which one he should fuck first. Until he decided, he stuck his tentacles inside them and began to properly stretch them. His free tentacles playfully teases their nipples making them hard and erect. Both boys shivered from his touch and odd pleasurable pain of Koro-sensei's tentacles inside them stretching them out. 

Nagisa and Karma moan through gritted teeth. It feels weird having their teacher's tentacles inside them rubbing against their walls and probing for their prostates. Koro-sensei finds their sweet spot and both boys gasp with pleasure. 

Nagisa could feel his penis throb as it became hard and clenched teeth even harder. He didn't want to enjoy this. He glances at Karma who seemed to be just as mortified, his penis already completely hard and erect. The sight made him blush even harder and his penis sprung up with anticipation. Guiltily, he looked away again wishing that he wasn't thinking of being fucked by Karma instead in this moment. 

Karma on the other hand was wondering what a sadist such as himself was doing secretly enjoying this. Was it because Nagisa was also there suffering with him? Perhaps he was more of a masochist than he realized. 

Koro-sensei withdrew his tentacles and grinned, pulling out his own penis and pointing it back and forth between the two boys as he decided who he was going to fuck first. 

"Hm~! Who shall it be, who shall it be?" He mused, wrapping his tentacles around their penises again and pumping them. "Nagisa? Karma?" 

Nagisa whimpered. He was terrified of having a mutant teacher stick his penis inside of him and was glad that he couldn't see what Koro-sensei's penis actually looked like. 

Turned on by the sound of Nagisa's whimper, Koro-sensei chose him, putting the head of his penis against Nagisa's twitching entrance. Nagisa stiffened and his trembling increased, tears prickling in his eyes. 

"I guess Nagisa should go first since he did expose himself to me before Karma~!" With that, Koro-sensei shoved himself into Nagisa making the boy yelp and began to thrust mercilessly. 

As Koro-sensei fucked him, all Nagisa could think of was how he was starting to enjoy the strange pain-filled pleasure that came with Koro-sensei's penis being rapidly thrusted inside of him. From the way it felt, it was clearly such bigger and thicker than Karma's which he had had the pleasure of sucking in the storage room during their free period. Karma and him hadn't had actual sex yet, and Nagisa was disappointed that Karma wouldn't be the first to fuck him. After this, he wasn't sure if Karma's penis would feel as good and Koro-sensei's did in that moment.

Karma was thinking something similar. Listening to his Nagisa's moans, he wondered if his boyfriend was actually enjoying being raped since he had some masochist tendencies in the storage room not too long ago. He also wondered if he would be able to pleasure Nagisa in the same way if Koro-sensei could do it better. 

Five minutes later, Koro-sensei finished inside Nagisa, and the young boy finished with him crying out as he released his load onto the desk. 

"Karma's turn now~!" Koro-sensei sang, already hard again. He was a mutant after all. If he wanted to, he could fuck both boys until midnight without feeling tired. But he didn't want to break them of course. 

Karma gasped when Koro-sensei shoved himself inside thrusting into him as mercilessly as he done with Nagisa. Karma's whole body burned with the pain and humiliation. One day he'd make Koro-sensei regret this. 

Nagisa glanced at Karma's face and couldn't help but feel turned on at his expression as Koro-sensei raped him. Without realizing, his penis started to become hard again. 

When Koro-sensei finished inside Karma, he noticed Nagisa's penis was hard again. "Looks like this isn't over yet~!" Karma hadn't finished at the same time with Koro-sensei like Nagisa did and before he could Koro-sensei used his tentacles to prevent him from coming. "Since I've got super speed, I can just fuck both of you at the same time!" 

Using his super speed, Koro-sensei went back and forth between the boys fucking them so hard and so fast that neither of them could tell when he completely pulled out of one to fuck the other. 

"It'll be like russian roulette," Koro-sensei joked. "Which one of you will receive my sperm this time?" 

Karma and Nagisa have never and would never moan this loud again in their entire lives. Koro-sensei was too much for them to take and it was incredibly hard not to enjoy the stimulation at this point. 

Finally, when neither could take it anymore Koro-sensei released his grip on their penises and the three of them came together. 

Nagisa was the one who got lucky and received Koro-sensei's sperm again. Trails of cum dripped down his legs and onto the floor. 

Koro-sensei released his hold on the boys. Breathing heavily and shaking, they got up and turned to face their teacher as he used his super speed to un-handcuff, clean, and redress them. 

"Did I tutor you well enough, Nagisa-kun?" Koro-sensei asked innocently. "If there's something you still don't understand, please feel free to drop by again."

Both boys glared at Koro-sensei. Neither of them wanted to admit that in the end they enjoyed their experience. 

"Don't think we won't try to get revenge for this," Karma warned. "We'll pay you back ten-fold." Nagisa nodded in agreement. 

"Well, it's time for me to head home now. See you boys in class tomorrow~!" Koro-sensei waved and took off like a rocket. 

The boys watched him go already planning their next move. They wouldn't fail again next time.


End file.
